First clean the mushrooms and cut them into small pieces. Peel the garlic and cut into slices. Cut sage leaves into strips.
Heat the oil in a pan and add the garlic. Then add the sage leaves and the mushrooms.
Saute over low heat and after 5 minutes add the cream. Season with salt and pepper.
Cook the spaghetti and drain, mix well in a bowl the spaghetti and mushroom sauce.
Arrange the pasta with the sauce on plates and serve.